The long-range goal of this project is to define the molecular mechanism by which the presence of alcoholic liver disease (ALD) increases the severity of the hepatitis C virus (HCV) infection or vice versa. The central hypothesis is that ALD produces oxidative stress, which enhances the cytotoxicity of tumor necrosis factor (TNF), a primary pathogenic mediator of liver diseases. We have previously shown that HCV core protein binds to the cytoplasmic domain of TNF receptor and sensitizes cells to TNF-induced cytolysis These factors together may count for the increased severity of the liver disease in these patients. In this project, we will establish cell lines expressing both CYP4502E1 enzyme, which is implicated in oxidative injury in ALD, and HCV core proteins. These cell lines will be tested for their cytotoxic responses to ethanol and TNF to examine their possible synergistic effects.